Various floor cleaning machines are known which apply the principle of a flexible bladder or membrane to reduce the overall size and weight of the cleaning machine by using the same tank space twice with the use of a flexible and movable inner container.
U.S. Pat. No. 3,896,520 discloses a vacuum cleaner which includes a rigid vacuum-retaining outer case which acts as a clean liquid reservoir, a flaccid spent liquid-retaining container within the case, a vacuum motor for creating vacuum within the case around the flaccid container including an inlet communicating with said case. The device has means communicating with the flaccid container for drawing discharged liquid and included dirt from the surface to be cleaned into the flaccid container under the influence of vacuum, so that the container fills with used liquid at a volume rate essentially equal to the rate of depletion of the unused liquid. The used or dirty liquid is disposed of by simply removing the top of the machine and dumping the liquid out. This procedure works fine for small machines of about five gallons. However, in large commercial and industrial cleaning machines, the reservoir usually contains twenty or thirty or more gallons (160-240 lb) and it is difficult or impossible to empty the machine by dumping. It would be impractical or impossible to lift the flaccid container from the machine when filled with spent dirty liquid because of its weight (approximately 160-240 lb) which, even if it could be done, would cause overstressing and damage to the flaccid container. In addition, the flaccid bag in U.S. Pat. No. 3,896,520 is smaller than the outer case which results in stress to the flaccid container as it fills with liquid. Repeated stressing will shorten the life of the flaccid container and can result in rupture of the flaccid container with unfavorable consequences, such as frequent and costly replacement of the flaccid container, the mixing of clean and used dirty solution, in turn, jamming and damaging the pump motor and costly repair and removal of debris with associated expensive down time in professional use of such equipment.
U.S. Pat. No. 4,196,492 discloses a carpet cleaning machine comprising a body which carries a storage means comprising a flexible bag for holding fresh cleaning solution which is received in an external rigid storage chamber. Spent dirty cleaning solution is collected in the external rigid storage chamber. The machine carries a scrubbing unit or means for cleaning the carpet. The scrubbing means includes a nozzle means for applying fresh cleaning solution to the carpet and a vacuum means for removing the spent cleaning solution from the carpet. The flexible bag of U.S. Pat. No. 4,196,492 is undersized and only partially supported by the walls of the external chamber when it is full resulting in severe localized stressing of the bag, shortening its life. This problem is also true of the alternate embodiment as well as U.S. Pat. No. 4,210,978 wherein the flexible bag is replaced by a plastic membrane.
In addition, while the flexible bag has a valve connection to the liquid spray system, it does not have a dump valve arrangement, additionally it is permanently mounted in place and cannot be removed for cleaning of the spent dirty solution rigid storage chamber without major dis-assembly of the whole unit. Even though the bag is filled with clean water, inevitably the interior of the bag becomes contaminated with minerals and other deposits, and the exterior storage chamber becomes contaminated by dirty water. With the flexible bag being permanently mounted to both the bottom spray head outlet and to the top part of the rigid tank body, it is inevitably subject to hazardous bacterial growth without the needed access for proper cleaning of the spent dirty solution tank which is exterior to the non-removable flexible bag.
U.S. Pat. No. 4,210,978 relates to a carpet cleaning machine comprising a body which carries a rigid storage chamber for holding fresh cleaning solution and a second storage chamber for receiving spent cleaning solution. A flexible membrane or partition divides an enclosed rigid cavity in the body into the first and second storage chambers. The flexible membrane is not supported and is simply permanently affixed (ref. page 12, line 30-35) at its extremities to the rigid cavity in the body such that there is severe stress when the second chamber is full of spent liquid. The membrane is not readily removable and inevitably becomes contaminated by the dirty spent cleaning liquid. This presents the same hazardous bacterial growth problem as the previously discussed U.S. Pat. No. 4,196,492. In addition it also does not have a dump valve connected directly to the flexible bag for easy vacating of the contained liquids.
Still further, U.S. Pat. No. 4,956,891 describes a floor cleaning machine comprising a support structure including a housing having a rigid water chamber, an inner spherical flexible container within the water chamber defining an inner chamber for retention of clean water. The machine of U.S. Pat. No. 4,956,891 does not provide any significant support for the spherical clean water chamber and thus stress is not prevented and eventual damage is inevitable. The spherical chamber is at the bottom permanently fixed to the spray head system outlet and at the top to the rigid tank body and thus is not adapted for ready removal from the machine. Therefore, the exterior of the flexible container and the return rigid waste tank surface becomes contaminated by dirty liquid and cannot be effectively cleaned without major disassembly of the whole unit, and thus will have the same hazardous bacterial growth problem as the previous discussed patents, U.S. Pat. Nos. 4,196,492 and 4,210,492. In addition it also does not have a dump valve connected directly to the flexible bag for easy vacating of the contained liquids.
None of the prior art devices is provided with means whereby a dump valve provides the emptying of both the flexible container and the rigid waste tank.
The present invention provides a novel cleaning machine in which the flexible flaccid container carries the dirty liquid and the dirty liquid can be easily removed by a dump valve in communication therewith. The bag is fully supported within the machine to avoid stress and provide long life. The flaccid container can be quickly disconnected and removed for easy cleaning. The machine of this invention is particularly adapted to large industrial and commercial machines of twenty, thirty or more gallons capacity. In the present invention, the flaccid container and the rigid waste tank can both be easily drained through a single dump valve.